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- Nov 26, 2009
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The FA head intake venturi is approx 32mm wide and 26mm tall which is a bit small. Good velocity and better midrange power. But I heard a report that they are not that great on top end - possibly less top end power. I have not tested one myself so I don't know and that's why I'm asking. Has any one made an objective comparison to a stock head such as:
750 30mm ports
850, RH4 32mm 32mm ports RH10 30mm ports
And all the negative talk about 32mm RH4 heads - with a dyno comparison - are they worse or better performance wise than the 30mm port RH10 head. Note that the screaming Combat had a 32mm port head. And there are a lot of Maney heads with ports larger than 32mm that have been winning races. There has also been tunning notes port specs and HP gain claims with 32mm ports.
I have always started with 28mm port heads and raised the ports while refering to Axtell port dimensions with great results, but have stayed away from the 32mm port heads which have a rep of being too big (even though my 850 race ported head was pushing 31 or 32mm at the venturi and 34 at the manifold.
There has been lots of talk but I haven't seen an objective dyno test.
750 30mm ports
850, RH4 32mm 32mm ports RH10 30mm ports
And all the negative talk about 32mm RH4 heads - with a dyno comparison - are they worse or better performance wise than the 30mm port RH10 head. Note that the screaming Combat had a 32mm port head. And there are a lot of Maney heads with ports larger than 32mm that have been winning races. There has also been tunning notes port specs and HP gain claims with 32mm ports.
I have always started with 28mm port heads and raised the ports while refering to Axtell port dimensions with great results, but have stayed away from the 32mm port heads which have a rep of being too big (even though my 850 race ported head was pushing 31 or 32mm at the venturi and 34 at the manifold.
There has been lots of talk but I haven't seen an objective dyno test.
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